Adjustable armrests are disclosed in U.S. Pat. Nos. 7,234,779, 6,840,582, 6,802,566, 6,659,561, 6,540,300, 5,975,640, 5,971,484, 5,876,097, 5,676,483, 5,599,067, 5,597,208, 5,484,187, 5,439,267, 5,415,459, 5,393,124, 5,265,938, 5,188,423, 5,056,863, and 4,961,610, U.S. Provisional Patent Application No. 60/953,213 and World Intellectual Property Organization Publication No. WO2008/112920. Such armrests typically permit a user to adjust an armrest laterally, rotationally, or longitudinally so the user may adjust the support provided to his arms when in a particular seated position.
The armrests may also be attached to a support that permits vertical adjustment of the armrests. For example, armrests may be supported on a tube that extends out of a support attached to a chair seat or chair base. As another example, the armrests may be attached to back frame side members such that the armrests are vertically moveable along the side members.
One problem many users experience with adjustable armrest designs is their inability to provide a sufficiently stable position. For instance, in some adjustable armrest designs, a user may freely move an armrest to a desired position. However, when a user may lean on the armrest, that armrest may move to an undesired position due to the force exerted on the armrest by the user.
Some armrest designs utilize a locking mechanism to address the issue of free moving armrest designs. For instance, the armrest design disclosed in World Intellectual Property Organization Publication No. WO2008/112920 utilizes a locking mechanism that locks the position of an armrest in a particular position. For a user to move the armrest, the user actuates the locking device to unlock the position of the armrest prior to adjusting the position of the armrest. The adjustment of such locking devices to an unlocked position can prevent a user from readily and easily adjusting the position of an armrest. For instance, such locking mechanisms often require a relatively high amount of force to press a button or actuate a lever to unlock the locking device prior to adjusting the position of the armrest.
An adjustable armrest device is needed that permits the adjustment of an armrest without the use of a locking device that requires the locking device to be placed in an unlocked position prior to adjusting the position of an armrest. Preferably, the adjustable armrest device will not require such a locking device for any rotational, longitudinal or lateral adjustment of the armrest. Such an armrest is also preferably configured to maintain its position when a user leans on the armrest while also permitting relatively easy adjustment of the armrest.